In recent years, as a fine electronic technology is developed, demand for a structure in which fine conductive patterns are formed on a surface of polymer resin substrates (or products) of various kinds of resin products or resin layers, and the like has been increased. The conductive patterns on the surface of the polymer resin substrate and the structure may be applied to form various targets such as antennas integrated into a cellular phone case, various kinds of sensors, MEMS structures, RFID tags, and the like.
In particular, recent portable devices such as a smart phone, and the like, need to have simultaneously mounted local area network functions such as communication, bluetooth, Wi-Fi, electronic payment, and the like, unlike the existing cellular phone, and the like, and due to this reason, it is required to simultaneously mount various antennas in one smart phone. However, since aesthetic design aspect of the portable devices such as the smart phone, and the like, in addition thereto, is emphasized, a method of forming conductive patterns capable of serving as various antennas on the surface of the polymer resin substrate such as the case of the portable devices, and the like, has been continuously suggested and researched so as to simultaneously meet these demands.
As the interest in the technology of forming conductive patterns on the surface of the polymer resin substrate has been increased, several technologies regarding this were suggested. For example, a method of forming conductive patterns on a polymer resin substrate by blending and molding specific inorganic additives containing transition metals such as copper, and the like, (for example, CuCr2O4 having a spinel structure, and the like) in a polymer resin chip to form a polymer resin substrate, directly radiating an electromagnetic wave such as laser, or the like, on a predetermined region, and plating the laser radiated region to form a metal layer was suggested. In this method, the inorganic additive-derived components in the laser radiated region are exposed and function as a seed for a kind of plating, such that the metal layer and conductive patterns may be formed.
However, since a substantial amount of high priced and specific inorganic additives should be used in the method for forming the conductive pattern, there is a disadvantage in that the total manufacturing cost is increased. In addition, since the inorganic additive needs to be blended into the polymer resin chip itself, the inorganic additive may deteriorate physical properties such as mechanical properties, dielectric constant, and the like, of the polymer resin substrate or resin products formed therefrom, or may cause dielectric loss.
Further, the specific inorganic additives such as CuCr2O4 having the spinel structure, and the like, have own unique colors, such that there is a limitation in implementing the polymer resin products, and the like, having colors desirable to consumers, for example, white color or other various colors. In particular, since most of the above-described inorganic additive has a dark color, when implementing the white or lighter colored products, and the like, by using the inorganic additive, color of the inorganic additive needs to be concealed by various pigments and the like, and even in the case of using Cu2(OH)PO4, Sb/SnO2, and the like, showing relatively light color in the inorganic additives, the same problems as mentioned above may occur even though there is a small difference.
Due to the disadvantages, a technology capable of forming fine conductive patterns by a simplified process on various kinds of the polymer resin products or the resin layers without containing the specific inorganic additives in the polymer resin itself has been demanded. However, in the case of simply omitting the adding of the specific inorganic additives, since the electromagnetic wave needs to be radiated by relatively strong power, the manufacturing cost may be rather increased, physical properties of the polymer resin product itself may be deteriorated, and there is a technical difficulty in that it is difficult to satisfactorily form fine conductive patterns.